Make-up valve for air system



Dec. 18, 1962 w. K. sTExNHAGE'N ETAL 3,058,831

MAKEUP VALVE FOR AIR SYSTEM Filed Feb. 6, 1959 2 Sheets-Sheet 2 '.Il y@2 fj ,f 1 .41 5

INV ENTORS ATTORNEY illiilll l United States Patent 3,ti68,81 MAKE-UiVALVE FR All?. SYSTEM Wiiiiam K. Steinhagen, Royal Galt, Mich., andRichard L. Merrell, Sinisbury, Conn., assignors to General MotorsCorporation, Detroit, ich., a corporation of Delaware Fied Feb. 6, 1959,Ser. No. 7%,7e6 2 Claims. (Si. 137-116) This invention relates generarlyto closed type pressurized fluid systems, and more particularly to amakeup valve and valving arrangement for replenishing lost air in such asystem.

A closed type pressurized fluid system differs from an open type systemin that a low pressure reservoir is provided to receive the dischargedduid from a working device; .the lluid is withdrawn by an air compressorand then compressed into a high pressure reservoir or re-use in theworking device. On the other hand, in the open type liuid system thecompressor continuously draws its fluid from the atmosphere orreplenishing the iluid that is vented or exhausted from the workingdevice.

Among the advantages of the closed type system over the open type systemare (l) the compressor, working with uid that is already at a pressureabove atmospheric i pressure, does not require as much power tor raisingthe pressurized uid to a higher pressure and thereby is rendered moreefficient; (2) the compressor does not have to operate as frequently tomaintain a predetermined pressure in the system. While these advantagesexist in such a system, some fluid will invariably escape the systemeither through the compressor, working device, or through the variousconnections. This iluid loss has a detrimental etfect on maintaining apredetermined pressure in the high pressure reservoir required foreffectively supplying fluid to the working device.

Accordingly, the objects of the present invention are to maintain thelow pressure tank orr a closed type pressurized iiuid system atpredetermined pressure; to admit atmospheric air to the system wheneverthe tank pressure drops below a predetermined value; to provide asupercharging of the compressor; to prevent the compressor from drawingair from a low pressure tank once the pressure therein falls below apredetermined value; and to provide means responsive to the pressure inthe low pressure reservoir for admitting fluid at atmospheric pressureinto a closed type pressurized fluid system.

Referring to the drawings wherein like reference numerals refer to likeparts, and wherein:

FG. 1 is a schematic diagram of a system embodying one form of valvingarrangement of the present invention;

FIG. 2 is an elevation view of a compressor head embodying the valvingarrangement of the present invention;

FIG. 3 is a horizontal sectional View taken on line 33 of FIG. 2;

FIG. 4 is an enlarged sectional view taken on line 4--4 of FIG. 3;

FIG. 5 is a sectional view taken on line 5 5 of FlG. 4; and

FIG. 6 is a sectional View of a further the present invention.

In FIG. l of the drawings, the pressurized fluid system embodying thepresent invention includes a compressor 19, a high pressure storage tank1l, a working device 12, a low pressure storage tank i3 and a make-upValve 14 all connected in series circuit.

rThe compressor it? is adapted to draw i-luid directly from theatmosphere or through the make-up Valve 14 from the low pressure storagetank 13 in a manner that will hereafter be explained. This liuid is thencompressed in the compressing chambers of the compressor il and pumpedthrough a connecting conduit to the high pressure embodiment oi storagetank il. A Working device 12, such as a pressurized fluid-operated brakeor spring, is operatively connected to the high pressure storage tank iland receives pressurized iluid therefrom. Fluid that is exhausted fromthe working device l2 during operation thereof is not lost to theatmosphere, as in an open type system, but directed through a suitableconnection to the low pressure storage tank 13, wherefrom the lluid isthen made available to the compressor 10 for re-use by the make-up valvei4.

While the compressor and makeup valve are shown as separate elements inFIG. 1, they may be combined into a single unit as illustrated in PEG.2. The compressor itl may be of a well known wobbler type compressorhaving .the make-up valve l?.- housed therein. rthe mechanism of thecompressor le is outlined by dotted lines; however, no portion thereofis encompassed in the present invention; consequently, a detaileddescription is omitted.

Referring now to FIG. 3, an air inlet port l5 is provided in the head ofthe compressor itand receives uid from the low pressure tank i3. A boreor chamber i6 having its longitudinal axis normal to the axis of theinlet port l5 is also provided in the housing of the compressor l@ andintersects the inlet port l5. The bore 'in has a spool valve 17positioned and slidably movable therein. The bore 16 communicates with apassage l that is axially aligned with `the bore and that leads to thecompressing chamber of the compressor. A further passage i9 providescommunication between passage i8 and the atmosphere. The passage i9 isprovided with an enlarged end portion having seated therein an aircleaner incorporated with a conventional check valve that is normallymaintained closed by a spring 2l. The cleaner 2t? filters any air beingadmitted to the compressor therethrough.

A detailed drawing or" the valving mechanism that is employed in thepresent invention is shown in FG. 4. The valve mechanism shown comprisesthe spool valve 17 which is substantially cylindrical in shape and hasenlarged portions 22 and reduced portions 23. A retaining memberconsisting of a head portion 2d, washer 25 and a threaded stud 26attached to the head 24 is iixedly attached to the spool valve 17. Thisretaining member serves to iixedly secure a diaphragm 27 to the valvet7. An enclosure 2S having outwardly extending flanges 29 encloses theretaining means. A vent 3i? is provided in the en closure 2S to maintainthe air therein at atmospheric pressure. adapted to compress theextremities of the diaphragm 27 to the housing of the compressor it? andthereby restrict any movement of the outer edges of the diaphragm 27.Fastening means for securing the enclosure flanges 29 to the compressor10 are not shown but can be of any suitable type. A helical spring 32 ispositioned within the enclosure 28 so as to surround the head 24 of theretaining means. One end of the spring 32 abuts the roof of theenclosure member 28, while the other end seated on the washer 25 biasesthe valve 17 against the seat 33 to close off the passage i8 andprevents communication between the inlet port l5 and the passage 18.

The enlarged portions 22 on the valve body i7, which can be seen moreclearly in FIG. 5, serve to guide the valve within the bore 16 of thecompressor head. Passages 34 are provided between the enlarged portions22 so as to permit the pressurized fluid entering into the compressorlil from the low pressure tank i3 through the fluid inlet port 15 to bedirected to the under side of the diaphragm 27 and to the area adjacentthe valve seat 33.

The operation of the valving arrangement illustrated in FIGS. 1 to S isas follows: Assuming the system is flrst to be charged with fluid, thevalve spool 17 is in a seated position due to the fact that the forcebeing exerted by the spring 32 on the washer 25 is greater than theforce exerted on the diaphragm 27 by the iluid in The llanges 29 of theenclosure member areinlet l5. Accordingly, the passage ftd to thecompressing chamber of the compressor l@ is closed. Consequently,operation of the compressor will mtablish a suction pressure which issucient to overcome the force of the spring 2i of the che-ck valve andthereby admit duid from the atmosphere to the compressing chambers ofthe compressor via the passage E9. The compressor lil will draw thetluid from the atmosphere through the check valve, compress it in thecompressing chambers, and discharge it at a higher pressure to the highpressure storage tank lll through a connecting conduit. The operation ofthe compressor iii will continue in this manner until the high pressuretank il attains a predetermined pressure. Then a governing device, whichis not shown, will automatically discontinue operation of the compressorlll. Upon iilling of the high pressure storage tank Ill VVwith a uid ata predetermined pressure, the working device l2 that is connectedthrough a conduit to the high pressure tank ll and that draws its fluidtherefrom will then be rendered operative. During ope-ration of teworking device i2, iiuid that is exhausted therefrom will be directed bymeans of a conduit to the low pressure tank 13. The operation of thesystem will continue as above enumerated until the low pressure tank 13attains a predetermined pressure above atmospheric pressure.

It should be kept in mind that due to the connection be-V tween the lowpressure tank V13 and the compressor 1t?, the pressure in the lowpressure tank 13 will also be the pressure in the inlet l5 of thecompressor 19 and will be in communication with the diaphragm 27 of thevalving arrangement. lhe pressurized tluid from the low pressure tank i3will tend Vto lift the diaphragm'27 upward,

Y Vthereby carrying the attached valve body 17 in the same directionwith it. Y VAt the same time the spring 32 tends to prevent opening ofthe valve.

Oncethe pressure from the low pressure tank 13 attains the predeterminedvalue, this pressure will overcome the force of the `spring 32 and thevalve body 17 will snap open, thereby establishing communication betweentheV low pressure tank 13 and the working chamber of the compressor lilby means of the conduit i8. The pressure in the low pressure tank 13being at a pressure greater than atmospheric and well above the suctionpressure of the compressor l@ will then cause the check valve to close.At this time, any air being drawn by the compressor 1? will be suppliedby the low pressure storage tank 13 to supercharge the compressor l@ andto permit the compressor to pump the duid into the high pressure tank11. After continuous operation in this manner, any fluid loss from thesystem due to leakages will'have the elTect of dropping the pressure inthe low pressure tanl 13 below a 'Value suihcient to maintain Vthe valvebody 17 open against tthe spring 32. When this occurs the Vspring Y y32will urge the valve body i7 downwardly to a seated position, resultingin a blocking of the inlet port 18, and once again the compressor l@will draw-fluid from the atmosphere through the check valve until thelost uid is replenished and the low pressure tank 13 again attains thepredetermined pressure required for opening the valve body 17 toestablish communication between the low pressure tank 13 and thecompressor fluid inlet port l5 A modiiication'of thevalve mechanism thatis incorpo-.

rated inthe subject invention is shown in FIG. 6.V This modiiicationisadapted to admit pressurized fluid into the compressor lt) at apredetermined pressure of the low `pressure storage tank, or when thepressure in theV tank s within a predetermined range of values, and topermit iluid at atmospheric pressure to enter the compressorV Y when thepressure Yinthe low pressure tank falls below the predetermined range ofvalues.VV In addition, this Ymodf ilication is adapted to prevent thepressurized duid in the low pressure storage tank fromY attaining lapressure Vsubstantially above the predetermined range kof values. Thisis'V accomplished Yby the provision of passages in the valveV 1mechanism housingrthat cooperate with a portedcylin'-Y 43 and the valvebody 44B and is adapted to securely fix the diaphragm 45 to the valvebody uponV proper tightening of the nut 43. An enclosure d6, having aconfiguration similar to the enclosure of the previously described Valvemechanism, is provided with a ilange portion 47 that is adapted torestrict movement et the outer extremities of the diaphragm i5 and alsohas a vent 4,8 to atmosphere provided therein. A spring 49 interposedbetween the enclosure 46 and the washer 44, as in the prior valve,maintains the valve body 4d in a seated position and thereby closes thepassage i8. A port 15 is provided for admitting pressurized liuid fromthe low ressure res.V

ervoir to a chamber adjacent the seating member 41. Passages 5u, 51 and52 are provided to convey the pressurized fluid from the chamber to theunder sides of the Y diaphragm 45. Passage 5l also leads to an enlargedopening 57 adjacent an annular groove 55 in a sleeve S4 and is adaptedto supply duid to the groove for purposes that will hereafter beexplained. The cylindrical sleeve Y i 54 surrounds the valve body 4d andis adapted to tixedly ride therewith. The annular groove 55 about theouter periphery of the sleeve 54 is capable of establishing com`munication between the passage 5l leading from the low pressure storagetank 13- and a passage 56 that leads to the atmosphere. The passage 56is positioned in a plane parallel to and slightly above that-of passage5l so that communication therebetween is not permitted until the annularVgroove 55 of the sleeve 54 is raised above the longitudinal axis of thepassage 51.

A check valve 53 slidably mounted in passage 19 is biased to a closedposition by a spring 58 for purposes'of admitting fluid from theatmosphere to the compressor chamber through the passage f t.

The operation of the subject modification is similar to that of thepreviously described valving mechanism. Pres! surized Huid from the lowpressure tank is admitted into the chamber adjacent the seating member41 through the port 15. This fluid is then supplied to the under sidesof the diaphragm 45 by the passages 5i), 51, 52 and tends to raise thediaphragm upwardly. The springV 4S prevents the raising of the diaphragmand attached valve body 40 until the pressure of the fluid overcomes theforce of the spring. Assuming the pressure of the liuid being directedto theY valve mechanism from the low pressure tank, for example, isat 43pounds per square inch (psi.) and the predetermined pressure requiredYto overcome the Vforce of the spring is 45 p.s.i., the valve 46 willremain seated to close port 18 until this latter pressureis attained.Once the predetermined'pressure is reached, the valve 4i) will besuiciently-raised to uncover the port 13. At this time the lluid fromthe low pressure tank will bedirected Yto the working chamber of thecompressor via the port 18. At the same time the pressurized fluid willact on the Vvalve 53, maintaining it closed Vto the atmosphere.

If the uidfrom the low pressure tank should rise 5 above the 45 p.s.i.required to unseat the valve 4t?, this additional pressure would have atendency to raise the However, to prevent the` pressure from increasingbeyonda predetermined value,

valve furtherV from its seat.

the bleed passage 56 to atmosphere is provided. Cornmunication betweenthe passage 5l, which isat'the pres.-V sure of the Vlovt pressure tank,and the bleed passage 56.7isA

established by the annular groove 5S in the sleeve S4 carried by thevalve body 4i?. Consequently, as the pressure m the low pressure tankincreases beyond p.s.i.Y this lexcessive pressureiwill urge thevalvebody d and its Y attached sleeve 54 upwardly until it reaches a positionwhere groove 55 establishes communication with the passage 56. Excessivepressure will then be exhausted to atmosphere via passage 51, opening57, groove 5S, and passage 56. As the pressure in the low pressure tankdecreases due to the bleeding 0E of the excessive pressure, the valvebody 40 will tend to be lowered by the spring 49 until the groove 55 isblocked from communication with passage 56 by the wall 59. Should thepressure in the low pressure tank continue to decrease to a value Ibelow45 p.s.i., the spring 49 will urge the valve body downwardly sucientlyto close the port 18 and thereby discontinue the supply of pressurizedfluid to the compressor. As in the previously described valvingmechanism, the compressors suction pressure will cause the check valve53 to open to admit fluid at atmospheric pressure to the compressor.

It is obvious that various changes may be made in details within thescope of our claims without departing from the spirit of our invention.It is, therefore, to be understood that our invention is not to belimited to the specific details shown and described.

What is claimed is:

1. A pressurized uid supply system comprising a compressor, a lowpressure tank, and a valve assembly for alternately connecting the inletof said compressor to atmosphere and to said low pressure tank, saidvalve assembly comprising a valve housing having a chamber therein,first passage means in said housing connecting the inlet of saidcompressor to said chamber and said low pressure tank, second passagemeans in said housing connecting said chamber directly to the atmosphereand a valve responsive to the pressure in said low pressure tank mountedfor movement within said chamber, al diaphragm secured to said valve foractuating said valve, one surface of said diaphragm being exposed to theatmosphere and the other surface exposed to the pressure in said lowpressure tank, a spring assembly engaging said surface of said diaphragmwhich is exposed to the atmosphere and urging said valve in a directionto bias said valve against said pressure of said low pressure tank, saidvalve being cylindrical in shape and having a cylindrical sleevesurrounding said valve and adapted to xedly ride therewith, and anannular groove about the outer periphery of said sleeve for establishingdirect communication between said chamber and the atmosphere, said valvebeing movable between a rst position at which said valve closes saidiirst and second passage means when the pressure within said lowpressure tank falls below a predetermined range of values, anintermediate position at which said iirst passage means is open and saidsecond passage means is closed when the pressure within said lowpressure tank is within said range of values and a third position atwhich said rst and second passage means are open when the pressurewithin said tank rises above said range of values, said valve meansincluding means being adapted to close said second passage means duringthe movement from said third position to sa-id intermediate positionwhile maintaining said rst passage means open. Y

2. A pressurized ud supply system as set forth in claim 1 wherein afurther passage means connects said rst passage means to atmosphere andwherein a valve responsive to the pressure diierence between atmosphereand the pressure in said iirst passage beans normally maintains saidfurther passage means closed when the pressure in said low pressure tankis within the above said predetermined range of values.

References Cited in the tile of this patent UNITED STATES PATENTS685,704 Wilkinson Oct. 29, 1901 1,999,697 Kleckner Apr. 30, 19352,070,411 Powers Peb. 9, 1937 2,177,082 Staa Oct. 2A, 1939 2,290,080Wahlmark July 14, 1942 2,848,249 Bertsch Aug. 19, 1958 2,862,725 JacksonDec. 2, 1958

